The present invention is related to an anchoring assembly part for a wind turbine tower for connection with a lower tower portion, made of a concrete material, and with an upper tower portion made of steel.
Wind turbine towers with tower portions from different materials are also called hybrid towers. The lower concrete-made tower portion is produced of a concrete material. Prefabricated concrete prefabs can be joined together on the construction site, or the concrete tower portion can be produced completely on the construction site by casting (in situ concrete). The steel-made tower portion can consist of plural tubular tower segments, wherein the individual tower segments are produced in one piece or joined together from plural elements that are distributed over the perimeter of the section.
Particular difficulties arise in the connection of the steel-made tower portion with the concrete-made tower portion. Here, different materials meet each other, which must be connected with utmost rigidity and which are subject to high dynamic loads.
For connecting the two tower portions, it is known from DE 603 11 894 T2, the entire contents of which is incorporated herein by reference, to embed an end region of the steel-made tower portion into the tower portion made from concrete. The embedded end region has anchoring elements, which are supposed to improve the support in the tower portion.
From DE 20 2006 009 554 U1, the entire contents of which is incorporated herein by reference, a special steel-made adapter element is known, which is cast together with the concrete-made tower portion. The adapter element is essentially realised in a ring shape and encloses the upper end of the concrete-made tower portion. On the upper side of the adapter element, a tubular tower segment made from steel is fastened by way of a flange connection.
Another annular adapter element is known from DE 102 30 273 B3, the entire contents of which is incorporated herein by reference. The same is also annular and is connected on its upper end with a tubular steel-made tower segment by way of a flange connection. The tower portion arranged below the adapter consists of prestressed concrete, wherein prestressing elements run in the interior of the wall of the lower tower portion and are guided through connection bores of the adapter element. The prestressing elements are anchored above the adapter element, so that they firmly prestress the adapter element with the concrete-made tower portion.
In the solution known from DE 10 2007 031 065 A1, the entire contents of which is incorporated herein by reference, the concrete-made tower portion has a head portion with diagonally arranged through bores. Anchor bolts are guided through these through bores, which can be fixed below the head portion by a nut. The anchor bolts are furthermore guided through bores in a flange of the upper steel-made tower portion, and fastened above this flange also by a nut. This known solution permits to replace the anchor bolts, but is constructionally sumptuous and requires a space-consuming head portion.
From the application document DE 23 041 32, the entire contents of which is incorporated herein by reference, a device for fastening machines on foundations is known. The known fastening device features an anchor sleeve, which is cast into the concrete of the foundation, wherein when casting the concrete, a protective pipe keeps open a bore for an expansion anchor that is to be received.
From the application document DE 20 39 263, the entire contents of which is incorporated herein by reference, an anchor sleeve for concrete prefabs is known, in which two sleeves for fastening a hoisting machine element are cast into the concrete and connected to the hoisting machine.
Starting from this, it is the objective of the present invention to provide an anchoring assembly part for a wind turbine tower for connection with a lower concrete-made tower portion, and with an upper steel-made tower portion, which meets the high rigidity requirements, is designed compactly and simplifies the construction of the tower.